When the alleged Boston Marathon bomber was told by one of his friends that he resembled one of the suspects in the widely released surveillance video, he sent a chilling response: "Lol, you better not text me," an affidavit unsealed Wednesday said.

The brief interaction between bombing suspect Dzhokhar Tsarnaev and his friend Dias Kadyrbayev occurred three days after the April 15 bombing, the affidavit said. Kadyrbayev was among three others charged Wednesday for allegedly conspiring to get rid of Dzhokhar Tsarnaev's incriminating backpack filled with gutted fireworks.

He also texted Kadyrbayev to say, "Come to my room and take whatever you want," according to the affidavit.

"Kadyrbayev knew when he saw the empty fireworks that Tsarnaev was involved in the marathon bombing," the affidavit reads. "Kadyrbayev decided to remove the backpack from the room in order to help his friend Tsarnaev avoid trouble."

The exchange came just a few hours before the Tsarnaev brothers would carjack a Chinese immigrant, murder an MIT police officer and engage in a wild shootout with police through the streets of Cambridge and Watertown, police say. Tamerlan Tsarnaev died April 19, after a shootout hours after authorities showed the brothers on surveillance video and named them as suspects.